Sunday, 12 April 2015

Abby Rabinowitz - a brief history of the meme

Some effort appears to have gone into the article: for one thing, Susan Blackmore, Daniel Dennett and James Gleick were apparently interviewed for it.

Abby seems to have some rather critical comments, though:

Yet, the very breadth of the concept makes it difficult to approach memes from the perspective of serious, observation-based science. In the analogy to genes, memes have inevitably disappointed. As Dawkins himself wrote, memes, as entities, are more vague than genes, where alleles compete to hold the same “chromosomal slots.” Unlike genes, memes are not directly observable and have high rates of mutation. Also, no one seems to be sure if memes exist. On the phone, Blackmore told me “the one good reason” memetics might not be a science: “There has been no example of where some scientific discovery has been made using meme theory, that couldn’t have been made any other way.”

Vagueness was, essentially one of John Maynard Smith's criticisms. IMO, he put it more eloquently, so I'll quote him:

The explanatory power of evolutionary theory rests largely on three assumptions: that mutation is non-adaptive, that acquired characters are not inherited, and that inheritance is Mendelian—that is, it is atomic, and we inherit the atoms, or genes, equally from our two parents, and from no one else. In the cultural analogy, none of these things is true. This must severely limit the ability of a theory of cultural inheritance to say what can happen and, more importantly, what cannot happen.

let's assume for a moment that his conclusion is true - and that it is harder to make predictions with cultural evolution than it is with biological evolution.

So what? Theories of cultural evolution are not in competition with theories of biological evolution - they compete with other theories of cultural change that are less inspired by Darwinism.

To expand on this, a theory making vague predictions doesn't make it bad. The issue is whether it does better than competing theories. Similarly, a ten-day whether forecast is going to have some sizeable error bars. That doesn't mean that it isn't the best quality forecast available. Nor does it mean that you should not heed its predictions.

I don't mean to grant the thesis that theories of cultural evolution really are vague (compared to the organic realm). That seems like a difficult claim to test - because you need to compare similar theories in the two realm - and what counts as 'similar' theories seems pretty subjective. I expect the jury will remain out on this issue for some time to come.

As for scientific discoveries that could not have been made without the meme concept - that seems like an unreasonable request to me. Science is Turing complete. Unless you destroy its foundations, prohibiting the use of scientific terminology or theories doesn't create a show-stopping situation. As with patents, there's usually some sort of work around.

The Copernican revolution is a good example of this. Without the concept of a heliocentric model, geocentric models still made accurate predictions. These models were ugly - but they worked and were consistent with the data. This historical episode illustrates how science can stagger on - even with a restricted set of models that excludes the most parsimonious ones.